


Day Fifteen

by InuShiek



Category: Transformers: Prime
Genre: Established Relationship, Inflation, M/M, NSFW, Orgasm Delay/Denial, Semi-Public Sex, Sex Toys, Sex Toys Under Clothing, Size Difference, Slash, Sticky, Vaginal Fingering, gaping
Language: English
Status: Completed
Published: 2014-08-20
Updated: 2014-08-20
Packaged: 2018-02-14 00:51:52
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,277
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2171688
Author URL: https://archiveofourown.org/users/InuShiek/pseuds/InuShiek
Summary: <blockquote class="userstuff">
              <p>It took some convincing for Knock Out to get Breakdown to say what one of his fetishes was, but he was eager to try it. Too bad he didn't really know what he was getting himself into.</p>
            </blockquote>





	Day Fifteen

**Author's Note:**

> I have no excuse for this other than it's my kink and I'm sticking to it.

At first it had seemed like a harmless little kink to indulge for the big blue mech. Knock Out had been curious why Breakdown had a toy like that in his subspace, but he hadn’t asked. He’d let the mech install it in his valve and lock his panel closed over it. That had made the medic nervous, but Breakdown had promised him that it would be enjoyable.

And the first day had been fun  _and_  enjoyable. Every so often, Breakdown would send a remote command for the toy in Knock Out’s valve to expand a bit. The red mech had gasped in surprise the first few times it happened, drawing some curious looks from any troops who happened to be in the medbay for maintenance each time.

That night, he’d ground his valve cover against Breakdown’s thigh, more than ready to interface, but the blue mech had simply wrapped him in a hug and contained his squirming. “That’s day one,” he’d said. “I’ll try to remember to send you a comm message before I expand it from now on. I’d hate for bots to start thinking you’re glitching.” Then he’d gone into recharge!

Day two had been worse. When Breakdown warned him that the toy was about to expand, his valve reflexively released still  _more_  excess lubricant. Frankly, Knock Out hadn’t understood how the fluid wasn’t leaking out onto his thighs. Breakdown had helpfully informed him that the toy takes in excessive lubricant when it expands, and the knowledge that Knock Out is essentially stuffed with his own fluid has the medic’s valve produce even more. Again, he’d rubbed his frame against Breakdown’s that night, but the larger mech had denied him and told him to rest.

By day seven, Knock Out had been fairly certain that he was going to die. At first, the toy had only stimulated him when he moved. Bending over or sitting at his desk had the thing pressing against his ceiling node. Now, however, it had expanded to a point where just _being_  there was stimulating every sensor in his stretched valve. “It should be just a little bigger than my spike now,” Breakdown had informed him. Still, Breakdown wouldn’t interface with him no matter how seductively he wriggled against the large mech. The blue bot would just wrap him up in a hug, half pin the squirming medic down, and tell him to recharge. He’d demanded to know why he couldn’t overload, even with the device jabbing his favorite node, and the mech explained, “It’s got an inhibitor, Doc.”

Day ten saw Knock Out barely able to work. He’d fallen into a routine, though. Breakdown would comm him, Knock Out’s valve would release a burst of lubricant, the poor medic would lay whatever he was handling down lest he damage it, then the toy would expand and he’d be hard pressed to remain standing. The device was so large now that there was nothing Knock Out could do to stop it from setting off every single node in his stretched valve. Every so often, his calipers would attempt to reset themselves, and all it accomplished was to weaken the medic’s knees while his valve rippled beyond his control.

By day fifteen, Knock Out wasn’t especially skilled at complex thought anymore. Because of this, he’d lost count of the days and had just surrendered himself his constant arousal, no possibility of overload, and no help from Breakdown.

That’s why he was so confused when Breakdown spread him out on the berth, rubbing his abdomen.

"Primus, I knew you’d be full, but I didn’t think your plating would actually have to start expanding," Breakdown breathes reverently. He’s never done this with a bot Knock Out’s size before, always with mechs his own size or even a bit larger.

Knock Out arches up into the touch, groaning incoherently when the toy jabs firmly into his ceiling node. If the thing hadn’t had an inhibitor, Knock Out would have overloaded a dozen times over easily. Large servos gently grasp his helm, guiding him to meet Breakdown’s optics.

"You ready, bitlet?" he asks, fighting to keep his panel closed. While Breakdown didn’t have a toy teasing him constantly for over two Earth weeks, he hadn’t overloaded either. It wouldn’t be at all fair, and the waiting is part of what makes this fun anyway.

Knock Out closes his optics, his entire frame quivering when he realizes that this is it. This is the night that his torment will be worth it. “Primus,  _PLEASE_.”

Breakdown unlocks the medic’s panel, and it snaps open before the locks are even fully disengaged. Lubricant floods out onto the berth, and the blue mech groans at the sight. The toy, still locked into Knock Out’s valve, is twice the size of Breakdown’s spike now. “Relax for me,” he requests before finally deactivating the lock on the toy. Beyond pleased that his smaller partner’s valve is so lax that it doesn’t immediately expel the toy, Breakdown eases it free.

In truth, Knock Out barely heard Breakdown ask him to relax, but his valve has been forced open for so long and stretched so far that it doesn’t require any physical effort on his part to keep it from contracting. “Breakdown?” he asks when his partner doesn’t move for a long moment, panting.

"You are so good to me," Breakdown praises, his optics still locked on the medic’s obscenely gaping valve.

"Please, Breakdown, just frag me. Please," Knock Out begs, servos groping blindly for blue plating to latch onto.

Allowing his panel to retract and freeing his aching spike, Breakdown doesn’t immediately comply with his partner’s request. Instead, he slides two of his digits into Knock Out’s valve, moaning when they don’t even touch the walls. “How does it feel?” he can’t resist asking.

Knock Out whines as more lubricant trickles out, “Empty!”

Knowing that the small mech is beyond desperate, having been teased and denied overload for so long, Breakdown takes pity on him. Grasping the back of Knock Out’s knees, the blue mech spreads his partner’s legs out and quickly slips his spike into him.

Breakdown shivers, groaning in pleasure. Knock Out always feels perfect- so snug and wet around his spike- but this….. Breakdown has always loved spiking smaller bots. The control he can have over them simply by looming over them combined with how tight they are for him are lovely.

But loose valves just….. The way they just brush against his spike, and, even when they clench down in overload, they aren’t as tight as a smaller valve.

When Knock Out had asked him what his fetish was, Breakdown had been reluctant to share. The medic has always had a penchant for dirty talk, usually including some mention of how tight his valve stays, and Breakdown didn’t want him to think that he didn’t very much appreciate it. The blue mech is pretty sure that Knock Out didn’t comprehend just  _how_  loose a valve he’d been talking about, but had agreed all the same.

For which Breakdown is immensely grateful.

He can feel Knock Out’s valve attempting to resize itself back down to fit the spike occupying it, but Breakdown is having none of that. Without further delay, he slips completely out of Knock Out’s valve, enjoying the view of the gaping valve one more time, before he slams back in, aiming for the ceiling node and tipping a very grateful medic into a violent overload.

Another thing Breakdown loves about loose valves? He can last twice as long, and he knows that the pretty red mech spread out beneath him loves to make interfacing last.


End file.
